Tilia Americana - Yellow leaves and black spots
I believe I have a basswood in my backyard (1461). It just started getting and dropping yellow leaves (1462). I looked underneath the tree and the bottom side of the leaves have black spots. Any idea what it might be. Sorry - tough to get a decent photo with the wind blowing 20+ mph.
Anoka County Minnesota
The photos lack the detail needed to determine what's causing the spots. Linden leaf blotch and basswood blotch miner damage are possibilities.
The first is a fungal disease (see photo three here):
The second is caused by an insect:
In any case, leaf miner and leaf spot disease damage is usually of little or no consequence so far as shade tree health is concerned. The spots can be unsightly but no control is recommended unless the damage is severe or causes frequent defoliation.